(1554) Evaluation of Time to Angiotensin II Administration on Responsiveness in Septic Shock

Introduction: Patients with septic shock require vasopressors to maintain organ perfusion and require immediate treatment. Prior to ATHOS-3, catecholamines and vasopressin were the only two classes of vasopressors available for the treatment of septic shock. With angiotensin II as another tool, the ideal time to initiate it in septic shock management remains undefined as well as the ideal background dose of combined vasopressors. The purpose of this study was to evaluate response to angiotensin II in patients with septic shock. We evaluated response and its potential relationship to early administration or combined vasopressor dose at time of initiation.

Methods: This was a single-center retrospective cohort study from March 2022 - December 2023 at a large academic medical center. Inclusion criteria were patients ≥18 years of age, received angiotensin II, and met the CDC Adult Sepsis Event Criteria. Patients were excluded if they received angiotensin II for shock not due to sepsis or if >48 hours had lapsed between time of first vasopressor and angiotensin II initiation. The primary outcomes for this study are: (1) whether the patient responded to angiotensin II and (2) inpatient mortality. Angiotensin II response was defined as a decrease in norepinephrine-equivalent dose (NED) of at least 0.1 mcg/kg/min at three hours after angiotensin II initiation. Key septic shock outcomes (inpatient mortality, hospital/ICU length of stay, and SOFA scores) were compared between angiotensin II responders and non-responders.

Results: A significant decrease in inpatient mortality was demonstrated for those responding favorably to angiotensin II (88% vs 61%, P < 0.0001). Time from first vasopressor to angiotensin II were not significant predictors of responsiveness. Although time and NED were not associated with response, NED was associated with inpatient mortality regardless of the responder status.

Conclusions: Although this study did not find time or NED to be associated with improved response to angiotensin II, mortality benefit was seen in those patients who were identified as responders to angiotensin II. While angiotensin II appears to improve clinical outcomes in patients with septic shock, its exact role and time during therapy have yet to be elucidated.